Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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11 pages, 1638 KiB  
Review
Aconitase: To Be or not to Be Inside Plant Glyoxysomes, That Is the Question
by Luigi De Bellis, Andrea Luvisi and Amedeo Alpi
Biology 2020, 9(7), 162; https://doi.org/10.3390/biology9070162 - 12 Jul 2020
Cited by 12 | Viewed by 7034
Abstract
After the discovery in 1967 of plant glyoxysomes, aconitase, one the five enzymes involved in the glyoxylate cycle, was thought to be present in the organelles, and although this was found not to be the case around 25 years ago, it is still [...] Read more.
After the discovery in 1967 of plant glyoxysomes, aconitase, one the five enzymes involved in the glyoxylate cycle, was thought to be present in the organelles, and although this was found not to be the case around 25 years ago, it is still suggested in some textbooks and recent scientific articles. Genetic research (including the study of mutants and transcriptomic analysis) is becoming increasingly important in plant biology, so metabolic pathways must be presented correctly to avoid misinterpretation and the dissemination of bad science. The focus of our study is therefore aconitase, from its first localization inside the glyoxysomes to its relocation. We also examine data concerning the role of the enzyme malate dehydrogenase in the glyoxylate cycle and data of the expression of aconitase genes in Arabidopsis and other selected higher plants. We then propose a new model concerning the interaction between glyoxysomes, mitochondria and cytosol in cotyledons or endosperm during the germination of oil-rich seeds. Full article
(This article belongs to the Section Plant Science)
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13 pages, 1419 KiB  
Article
CoVid-19 Pandemic Trend Modeling and Analysis to Support Resilience Decision-Making
by Romney B. Duffey and Enrico Zio
Biology 2020, 9(7), 156; https://doi.org/10.3390/biology9070156 - 7 Jul 2020
Cited by 11 | Viewed by 4501
Abstract
Policy decision-making for system resilience to a hazard requires the estimation and prediction of the trends of growth and decline of the impacts of the hazard. With focus on the recent worldwide spread of CoVid-19, we take the infection rate as the relevant [...] Read more.
Policy decision-making for system resilience to a hazard requires the estimation and prediction of the trends of growth and decline of the impacts of the hazard. With focus on the recent worldwide spread of CoVid-19, we take the infection rate as the relevant metric whose trend of evolution to follow for verifying the effectiveness of the countermeasures applied. By comparison with the theories of growth and recovery in coupled socio-medical systems, we find that the data for many countries show infection rate trends that are exponential in form. In particular, the recovery trajectory is universal in trend and consistent with the learning theory, which allows for predictions useful in the assistance of decision-making of emergency recovery actions. The findings are validated by extensive data and comparison to medical pandemic models. Full article
(This article belongs to the Special Issue Coronavirus Disease 2019 (COVID-19))
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17 pages, 4366 KiB  
Article
Norpa Signalling and the Seasonal Circadian Locomotor Phenotype in Drosophila
by Carlo Breda, Ezio Rosato and Charalambos P. Kyriacou
Biology 2020, 9(6), 130; https://doi.org/10.3390/biology9060130 - 16 Jun 2020
Cited by 4 | Viewed by 4948
Abstract
In this paper, we review the role of the norpA-encoded phospholipase C in light and thermal entrainment of the circadian clock in Drosophila melanogaster. We extend our discussion to the role of norpA in the thermo-sensitive splicing of the per 3′ UTR [...] Read more.
In this paper, we review the role of the norpA-encoded phospholipase C in light and thermal entrainment of the circadian clock in Drosophila melanogaster. We extend our discussion to the role of norpA in the thermo-sensitive splicing of the per 3′ UTR, which has significant implications for seasonal adaptations of circadian behaviour. We use the norpA mutant-generated enhancement of per splicing and the corresponding advance that it produces in the morning (M) and evening (E) locomotor component to dissect out the neurons that are contributing to this norpA phenotype using GAL4/UAS. We initially confirmed, by immunocytochemistry and in situ hybridisation in adult brains, that norpA expression is mostly concentrated in the eyes, but we were unable to unequivocally reveal norpA expression in the canonical clock cells using these methods. In larval brains, we did see some evidence for co-expression of NORPA with PDF in clock neurons. Nevertheless, downregulation of norpA in clock neurons did generate behavioural advances in adults, with the eyes playing a significant role in the norpA seasonal phenotype at high temperatures, whereas the more dorsally located CRYPTOCHROME-positive clock neurons are the likely candidates for generating the norpA behavioural effects in the cold. We further show that knockdown of the related plc21C encoded phospholipase in clock neurons does not alter per splicing nor generate any of the behavioural advances seen with norpA. Our results with downregulating norpA and plc21C implicate the rhodopsins Rh2/Rh3/Rh4 in the eyes as mediating per 3′ UTR splicing at higher temperatures and indicate that the CRY-positive LNds, also known as ‘evening’ cells are likely mediating the low-temperature seasonal effects on behaviour via altering per 3′UTR splicing. Full article
(This article belongs to the Special Issue Biological Clocks)
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12 pages, 2574 KiB  
Article
Period of Boar Ejaculate Collection Contributes to the Yearly Intra-Male Variability of Seminal Plasma Cytokines
by Lorena Padilla, Xiomara Lucas, Inmaculada Parrilla, Cristina Perez-Patiño, Heriberto Rodriguez-Martinez, Jordi Roca and Isabel Barranco
Biology 2020, 9(5), 105; https://doi.org/10.3390/biology9050105 - 20 May 2020
Cited by 4 | Viewed by 3062
Abstract
The concentrations of cytokines in seminal plasma (SP) fluctuate over time in healthy males, weakening their practical usefulness as diagnostic tools. This study evaluated the relevance of intra-male variability in SP cytokines and to what extent the period of the year when ejaculate [...] Read more.
The concentrations of cytokines in seminal plasma (SP) fluctuate over time in healthy males, weakening their practical usefulness as diagnostic tools. This study evaluated the relevance of intra-male variability in SP cytokines and to what extent the period of the year when ejaculate is collected contributes to such variability. Thirteen cytokines (GM-CSF, IFNγ, IL-1α, IL-1β, IL-1ra, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-18, and TNFα) were measured using the Luminex xMAP® technology for 180 SP samples of ejaculate collected over a year from nine healthy and fertile boars. The SP samples were grouped into two annual periods according to decreasing or increasing daylight and ambient temperature. Intra-male variability was higher than inter-male variability for all cytokines. All SP cytokines showed concentration differences between the two periods of the year, showing the highest concentration during the increasing daylength/temperature period, irrespective of the male. Similarly, some cytokines showed differences between daylength/temperature periods when focusing on their total amount in the ejaculate. No strong relationship (explaining more than 50% of the total variance) was found between annual fluctuations in SP-cytokine levels and semen parameters. In conclusion, the period of the year during which ejaculates were collected helps explain the intra-male variability of SP-cytokine levels in breeding boars. Full article
(This article belongs to the Section Immunology)
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19 pages, 5401 KiB  
Article
Isolation and Identification of Fusarium spp., the Causal Agents of Onion (Allium cepa) Basal Rot in Northeastern Israel
by Ben Kalman, Dekel Abraham, Shaul Graph, Rafael Perl-Treves, Yael Meller Harel and Ofir Degani
Biology 2020, 9(4), 69; https://doi.org/10.3390/biology9040069 - 2 Apr 2020
Cited by 56 | Viewed by 13992
Abstract
Over the past decade, there have been accumulating reports from farmers and field extension personnel on the increasing incidence and spread of onion (Allium cepa) bulb basal rot in northern Israel. The disease is caused mainly by Fusarium species. Rotting onion [...] Read more.
Over the past decade, there have been accumulating reports from farmers and field extension personnel on the increasing incidence and spread of onion (Allium cepa) bulb basal rot in northern Israel. The disease is caused mainly by Fusarium species. Rotting onion bulbs were sampled from fields in the Golan Heights in northeastern Israel during the summers of 2017 and 2018. Tissue from the sampled onion bulbs was used for the isolation and identification of the infecting fungal species using colony and microscopic morphology characterization. Final confirmation of the pathogens was performed with PCR amplification and sequencing using fungi-specific and Fusarium species-specific primers. Four Fusarium spp. isolates were identified in onion bulbs samples collected from the contaminated field: F. proliferatum, F. oxysporum f. sp. cepae, and two species less familiar as causative agents of this disease, F. acutatum and F. anthophilium. Phylogenetic analysis revealed that these species subdivided into two populations, a northern group isolated from white (Riverside cv.) onion bulbs, and a southern group isolated from red (565/505 cv.) bulbs. Pathogenicity tests conducted with seedlings and bulbs under moist conditions proved that all species could cause the disease symptoms, but with different degrees of virulence. Inoculating seeds with spore suspensions of the four species, in vitro, significantly reduced seedlings’ germination rate, hypocotyl elongation, and fresh biomass. Mature onion bulbs infected with the fungal isolates produced typical rot symptoms 14 days post-inoculation, and the fungus from each infected bulb was re-isolated and identified to satisfy Koch’s postulates. The onion bulb assay also reflected the degree of sensitivity of different onion cultivars to the disease. This work is the first confirmed report of the direct and primary cause of Fusarium onion basal rot disease in northeastern Israel. These findings are a necessary step towards uncovering the mycoflora of the diseased onion plants and developing a preventive program that would reduce the disease damage. Full article
(This article belongs to the Special Issue Plant-Pathogen Interaction)
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7 pages, 276 KiB  
Opinion
Is It Time to Rethink Our Weight Loss Paradigms?
by Paulo Gentil, Ricardo Borges Viana, João Pedro Naves, Fabrício Boscolo Del Vecchio, Victor Coswig, Jeremy Loenneke and Claudio André Barbosa de Lira
Biology 2020, 9(4), 70; https://doi.org/10.3390/biology9040070 - 2 Apr 2020
Cited by 9 | Viewed by 8175
Abstract
Strategies aiming to promote weight loss usually include anything that results in an increase in energy expenditure (exercise) or a decrease in energy intake (diet). However, the probability of losing weight is low and the probability of sustained weight loss is even lower. [...] Read more.
Strategies aiming to promote weight loss usually include anything that results in an increase in energy expenditure (exercise) or a decrease in energy intake (diet). However, the probability of losing weight is low and the probability of sustained weight loss is even lower. Herein, we bring some questions and suggestions about the topic, with a focus on exercise interventions. Based on the current evidence, we should look at how metabolism changes in response to interventions instead of counting calories, so we can choose more efficient models that can account for the complexity of human organisms. In this regard, high-intensity training might be particularly interesting as a strategy to promote fat loss since it seems to promote many physiological changes that might favor long-term weight loss. However, it is important to recognize the controversy of the results regarding interval training (IT), which might be explained by the large variations in its application. For this reason, we have to be more judicious about how exercise is planned and performed and some factors, like supervision, might be important for the results. The intensity of exercise seems to modulate not only how many calories are expended after exercise, but also where they came from. Instead of only estimating the number of calories ingested and expended, it seems that we have to act positively in order to create an adequate environment for promoting healthy and sustainable weight loss. Full article
(This article belongs to the Section Physiology)
24 pages, 1292 KiB  
Communication
Assessing Autophagy in Archived Tissue or How to Capture Autophagic Flux from a Tissue Snapshot
by Magali Humbert, María Morán, Patricia de la Cruz-Ojeda, Jordi Muntané, Tabea Wiedmer, Nadezda Apostolova, Sharon L. McKenna, Guillermo Velasco, Walter Balduini, Leopold Eckhart, Bassam Janji, Belém Sampaio-Marques, Paula Ludovico, Eva Žerovnik, Rupert Langer, Aurel Perren, Nikolai Engedal and Mario P. Tschan
Biology 2020, 9(3), 59; https://doi.org/10.3390/biology9030059 - 21 Mar 2020
Cited by 14 | Viewed by 6816
Abstract
Autophagy is a highly conserved degradation mechanism that is essential for maintaining cellular homeostasis. In human disease, autophagy pathways are frequently deregulated and there is immense interest in targeting autophagy for therapeutic approaches. Accordingly, there is a need to determine autophagic activity in [...] Read more.
Autophagy is a highly conserved degradation mechanism that is essential for maintaining cellular homeostasis. In human disease, autophagy pathways are frequently deregulated and there is immense interest in targeting autophagy for therapeutic approaches. Accordingly, there is a need to determine autophagic activity in human tissues, an endeavor that is hampered by the fact that autophagy is characterized by the flux of substrates whereas histology informs only about amounts and localization of substrates and regulators at a single timepoint. Despite this challenging task, considerable progress in establishing markers of autophagy has been made in recent years. The importance of establishing clear-cut autophagy markers that can be used for tissue analysis cannot be underestimated. In this review, we attempt to summarize known techniques to quantify autophagy in human tissue and their drawbacks. Furthermore, we provide some recommendations that should be taken into consideration to improve the reliability and the interpretation of autophagy biomarkers in human tissue samples. Full article
(This article belongs to the Special Issue Autophagy in Cancer)
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16 pages, 1852 KiB  
Article
Effect of Tillage System and Cover Crop on Maize Mycorrhization and Presence of Magnaporthiopsis maydis
by Mariana Patanita, Maria Doroteia Campos, Maria do Rosário Félix, Mário Carvalho and Isabel Brito
Biology 2020, 9(3), 46; https://doi.org/10.3390/biology9030046 - 3 Mar 2020
Cited by 32 | Viewed by 4893
Abstract
The sustainability of agriculture requires the adoption of agricultural soil conservation practices with positive impacts on soil quality, which can promote beneficial soil microbiota like arbuscular mycorrhizal fungi (AMF) and its diversity. This study aims to assess the influence of the presence of [...] Read more.
The sustainability of agriculture requires the adoption of agricultural soil conservation practices with positive impacts on soil quality, which can promote beneficial soil microbiota like arbuscular mycorrhizal fungi (AMF) and its diversity. This study aims to assess the influence of the presence of intact extraradical mycelium as a preferential source of inoculum of the native AMF in order to guarantee a better colonization as well as its possible bioprotective effect against Magnaporthiopsis maydis. In order to vary the available extraradical mycelium, two experiments, with and without cover crop, were carried out, in which two tillage systems and two maize varieties were studied. The capitalization of the benefits, in terms of grain production and M. maydis presence, associated to the cover crop were only achieved with minimum tillage. Therefore, both cultural practices are necessary to reduce the fungus presence, coupling the effect of mycorrhization together with other benefits associated with the cover crop. Although in the absence of a cover crop and using conventional tillage, yields and lower levels of M. maydis are possibly achieved, this system is more dependent on the variety used, does not benefit from the advantages associated with the cover crop, is more expensive, and environmentally unsustainable. Full article
(This article belongs to the Special Issue Plant-Pathogen Interaction)
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18 pages, 2212 KiB  
Article
Genetic Diversity and Identification of Vietnamese Paphiopedilum Species Using DNA Sequences
by Huyen-Trang Vu, Quoc-Luan Vu, Thanh-Diem Nguyen, Ngan Tran, Thanh-Cong Nguyen, Phuong-Nam Luu, Duy-Duong Tran, Truong-Khoa Nguyen and Ly Le
Biology 2020, 9(1), 9; https://doi.org/10.3390/biology9010009 - 31 Dec 2019
Cited by 15 | Viewed by 7878
Abstract
Paphiopedilum is among the most popular ornamental orchid genera due to its unique slipper flowers and attractive leaf coloration. Most of the Paphiopedilum species are in critical danger due to over-exploitation. They were listed in Appendix I of the Convention on International Trade [...] Read more.
Paphiopedilum is among the most popular ornamental orchid genera due to its unique slipper flowers and attractive leaf coloration. Most of the Paphiopedilum species are in critical danger due to over-exploitation. They were listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which prevents their being traded across borders. While most Paphiopedilum species are distinctive, owing to their respective flowers, their vegetative features are more similar and undistinguished. Hence, the conservation of these species is challenging, as most traded specimins are immature and non-flowered. An urgent need exists for effective identification methods to prevent further illegal trading of Paphiopedilum species. DNA barcoding is a rapid and sensitive method for species identification, at any developmental stage, using short DNA sequences. In this study, eight loci, i.e., ITS, LEAFY, ACO, matK, trnL, rpoB, rpoC1, and trnH-psbA, were screened for potential barcode sequences on the Vietnamese Paphiopedilum species. In total, 17 out of 22 Paphiopedilum species were well identified. The studied DNA sequences were deposited to GenBank, in which Paphiopedilum dalatense accessions were introduced for the first time. ACO, LEAFY, and trnH-psbA were limited in amplification rate for Paphiopedilum. ITS was the best single barcode. Single ITS could be used along with nucleotide polymorphism characteristics for species discrimination. The combination of ITS + matK was the most efficient identification barcode for Vietnamese Paphiopedilum species. This barcode also succeeded in recognizing misidentified or wrongly-named traded samples. Different bioinformatics programs and algorithms for establishing phylogenetic trees were also compared in the study to propose quick, simple, and effective tools for practical use. It was proved that both the Bayesian Inference method in the MRBAYES program and the neighbor-joining method in the MEGA software met the criteria. Our study provides a barcoding database of Vietnamese Paphiopedilum which may significantly contribute to the control and conservation of these valuable species. Full article
(This article belongs to the Section Conservation Biology and Biodiversity)
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12 pages, 916 KiB  
Article
Consequences of Haemorrhagic Smolt Syndrome (HSS) for the Immune Status of Atlantic salmon (Salmo salar L.) (Case Study)
by Aleksei Krasnov, Ingunn Sommerset, Tina Søfteland, Sergey Afanasyev, Preben Boysen and Hege Lund
Biology 2020, 9(1), 1; https://doi.org/10.3390/biology9010001 - 19 Dec 2019
Cited by 3 | Viewed by 4007
Abstract
Haemorrhagic smolt syndrome (HSS) is a disorder of unknown aetiology causing losses in the fresh water phase of Atlantic salmon farming. Normally, the mortality is limited and symptoms disappear upon seawater exposure. In this case study, classical HSS pathology with internal organ haemorrhages [...] Read more.
Haemorrhagic smolt syndrome (HSS) is a disorder of unknown aetiology causing losses in the fresh water phase of Atlantic salmon farming. Normally, the mortality is limited and symptoms disappear upon seawater exposure. In this case study, classical HSS pathology with internal organ haemorrhages and nephrocalcinosis was diagnosed, and the losses were substantial. Microarray analyses of head kidney revealed association between HSS and enhanced expression of stress genes and proteins reducing bioavailability of iron, heme, and retinol. In parallel, suppression of multiple metabolic pathways was observed. Up-regulation of genes encoding acute phase proteins, complement, and lectins indicated mild inflammation but without characteristic features of viral or bacterial infections. Microarray analyses highlighted several members of tumor necrosis factor receptor superfamily that may control development of B-cell immunity. Examination of IgM at the mRNA and protein levels showed the impact of HSS on vaccine responses. In fish without HSS symptoms (non-HSS), titres of vaccine specific antibodies to A-layer of Aeromonas salmonicida subsp. salmonicida and Moritella viscosa and antibodies binding to DNP-keyhole limpet hemocyanin (DNP-KLH), which are presumably polyreactive, were respectively four- and 14-fold higher than in HSS-diseased fish. Parallel sequencing of variable regions of immunoglobulin Mrevealed a larger size of most abundant clonotypes shared by multiple individuals in the non-HSS group. The results of the current case study indicated that, in addition to direct damage, HSS suppresses humoral immune responses including the production of specific and polyreactive antibodies. Full article
(This article belongs to the Section Immunology)
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19 pages, 2740 KiB  
Article
Combined Effects of Acute Temperature Change and Elevated pCO2 on the Metabolic Rates and Hypoxia Tolerances of Clearnose Skate (Rostaraja eglanteria), Summer Flounder (Paralichthys dentatus), and Thorny Skate (Amblyraja radiata)
by Gail D. Schwieterman, Daniel P. Crear, Brooke N. Anderson, Danielle R. Lavoie, James A. Sulikowski, Peter G. Bushnell and Richard W. Brill
Biology 2019, 8(3), 56; https://doi.org/10.3390/biology8030056 - 26 Jul 2019
Cited by 29 | Viewed by 8125
Abstract
Understanding how rising temperatures, ocean acidification, and hypoxia affect the performance of coastal fishes is essential to predicting species-specific responses to climate change. Although a population’s habitat influences physiological performance, little work has explicitly examined the multi-stressor responses of species from habitats differing [...] Read more.
Understanding how rising temperatures, ocean acidification, and hypoxia affect the performance of coastal fishes is essential to predicting species-specific responses to climate change. Although a population’s habitat influences physiological performance, little work has explicitly examined the multi-stressor responses of species from habitats differing in natural variability. Here, clearnose skate (Rostaraja eglanteria) and summer flounder (Paralichthys dentatus) from mid-Atlantic estuaries, and thorny skate (Amblyraja radiata) from the Gulf of Maine, were acutely exposed to current and projected temperatures (20, 24, or 28 °C; 22 or 30 °C; and 9, 13, or 15 °C, respectively) and acidification conditions (pH 7.8 or 7.4). We tested metabolic rates and hypoxia tolerance using intermittent-flow respirometry. All three species exhibited increases in standard metabolic rate under an 8 °C temperature increase (Q10 of 1.71, 1.07, and 2.56, respectively), although this was most pronounced in the thorny skate. At the lowest test temperature and under the low pH treatment, all three species exhibited significant increases in standard metabolic rate (44–105%; p < 0.05) and decreases in hypoxia tolerance (60–84% increases in critical oxygen pressure; p < 0.05). This study demonstrates the interactive effects of increasing temperature and changing ocean carbonate chemistry are species-specific, the implications of which should be considered within the context of habitat. Full article
(This article belongs to the Special Issue Fish Metabolic Physiology in Response to Stress)
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8 pages, 1330 KiB  
Article
N-acetyl-L-cysteine Prevents Lactate-Mediated PGC1-alpha Expression in C2C12 Myotubes
by Minas Nalbandian, Zsolt Radak and Masaki Takeda
Biology 2019, 8(2), 44; https://doi.org/10.3390/biology8020044 - 10 Jun 2019
Cited by 11 | Viewed by 5082
Abstract
Background: Exercise induces many physiological adaptations. Recently, it has been proposed that some of these adaptations are induced by exercise-mediated lactate production. In this study, we aimed to investigate in vitro the effect of lactate in cultured myotubes and whether antioxidants could inhibit [...] Read more.
Background: Exercise induces many physiological adaptations. Recently, it has been proposed that some of these adaptations are induced by exercise-mediated lactate production. In this study, we aimed to investigate in vitro the effect of lactate in cultured myotubes and whether antioxidants could inhibit the effect. Methods: Differentiated myotubes were cultured at different concentrations of L-lactate (0, 10, 30, 50 mM) in the absence or presence of an antioxidant, N-acetyl-L-cysteine (Nac). The temporal effect of lactate exposure in myotubes was also explored. Results: Two hours of exposure to 50 mM L-lactate and six hours of exposure to 30 or 50 mM L-lactate caused a significant increase in PGC1-alpha (peroxisome proliferator-activated receptor γ coactivator-1α) expression in the myotubes. This up-regulation was suppressed by 2 mM Nac. Intermittent and continuous lactate exposure caused similar PGC1-alpha up-regulation. These results suggest that the increase in PGC1-alpha expression is mediated by reactive oxygen species (ROS) production from lactate metabolism and that both continuous and intermittent exposure to L-lactate can cause the up-regulation. Full article
(This article belongs to the Section Cell Biology)
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15 pages, 1249 KiB  
Review
From Powerhouse to Perpetrator—Mitochondria in Health and Disease
by Nima B. Fakouri, Thomas Lau Hansen, Claus Desler, Sharath Anugula and Lene Juel Rasmussen
Biology 2019, 8(2), 35; https://doi.org/10.3390/biology8020035 - 11 May 2019
Cited by 15 | Viewed by 7319
Abstract
In this review we discuss the interaction between metabolic stress, mitochondrial dysfunction, and genomic instability. Unrepaired DNA damage in the nucleus resulting from excess accumulation of DNA damages and stalled replication can initiate cellular signaling responses that negatively affect metabolism and mitochondrial function. [...] Read more.
In this review we discuss the interaction between metabolic stress, mitochondrial dysfunction, and genomic instability. Unrepaired DNA damage in the nucleus resulting from excess accumulation of DNA damages and stalled replication can initiate cellular signaling responses that negatively affect metabolism and mitochondrial function. On the other hand, mitochondrial pathologies can also lead to stress in the nucleus, and cause sensitivity to DNA-damaging agents. These are examples of how hallmarks of cancer and aging are connected and influenced by each other to protect humans from disease. Full article
(This article belongs to the Special Issue Mitochondrial Dysfunction in Aging and Diseases of Aging)
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26 pages, 10469 KiB  
Review
Mitochondrial Dysfunction in Parkinson’s Disease—Cause or Consequence?
by Chun Chen, Doug M. Turnbull and Amy K. Reeve
Biology 2019, 8(2), 38; https://doi.org/10.3390/biology8020038 - 11 May 2019
Cited by 207 | Viewed by 25115
Abstract
James Parkinson first described the motor symptoms of the disease that took his name over 200 years ago. While our knowledge of many of the changes that occur in this condition has increased, it is still unknown what causes this neurodegeneration and why [...] Read more.
James Parkinson first described the motor symptoms of the disease that took his name over 200 years ago. While our knowledge of many of the changes that occur in this condition has increased, it is still unknown what causes this neurodegeneration and why it only affects some individuals with advancing age. Here we review current literature to discuss whether the mitochondrial dysfunction we have detected in Parkinson’s disease is a pathogenic cause of neuronal loss or whether it is itself a consequence of dysfunction in other pathways. We examine research data from cases of idiopathic Parkinson’s with that from model systems and individuals with familial forms of the disease. Furthermore, we include data from healthy aged individuals to highlight that many of the changes described are also present with advancing age, though not normally in the presence of severe neurodegeneration. While a definitive answer to this question may still be just out of reach, it is clear that mitochondrial dysfunction sits prominently at the centre of the disease pathway that leads to catastrophic neuronal loss in those affected by this disease. Full article
(This article belongs to the Special Issue Mitochondrial Dysfunction in Aging and Diseases of Aging)
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18 pages, 1335 KiB  
Review
Mitochondria and Aging—The Role of Exercise as a Countermeasure
by Mats I Nilsson and Mark A Tarnopolsky
Biology 2019, 8(2), 40; https://doi.org/10.3390/biology8020040 - 11 May 2019
Cited by 68 | Viewed by 25074
Abstract
Mitochondria orchestrate the life and death of most eukaryotic cells by virtue of their ability to supply adenosine triphosphate from aerobic respiration for growth, development, and maintenance of the ‘physiologic reserve’. Although their double-membrane structure and primary role as ‘powerhouses of the cell’ [...] Read more.
Mitochondria orchestrate the life and death of most eukaryotic cells by virtue of their ability to supply adenosine triphosphate from aerobic respiration for growth, development, and maintenance of the ‘physiologic reserve’. Although their double-membrane structure and primary role as ‘powerhouses of the cell’ have essentially remained the same for ~2 billion years, they have evolved to regulate other cell functions that contribute to the aging process, such as reactive oxygen species generation, inflammation, senescence, and apoptosis. Biological aging is characterized by buildup of intracellular debris (e.g., oxidative damage, protein aggregates, and lipofuscin), which fuels a ‘vicious cycle’ of cell/DNA danger response activation (CDR and DDR, respectively), chronic inflammation (‘inflammaging’), and progressive cell deterioration. Therapeutic options that coordinately mitigate age-related declines in mitochondria and organelles involved in quality control, repair, and recycling are therefore highly desirable. Rejuvenation by exercise is a non-pharmacological approach that targets all the major hallmarks of aging and extends both health- and lifespan in modern humans. Full article
(This article belongs to the Special Issue Mitochondrial Dysfunction in Aging and Diseases of Aging)
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22 pages, 1875 KiB  
Review
The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker
by Michael H. Hastings, Elizabeth S. Maywood and Marco Brancaccio
Biology 2019, 8(1), 13; https://doi.org/10.3390/biology8010013 - 11 Mar 2019
Cited by 130 | Viewed by 14802
Abstract
The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants ( [...] Read more.
The past twenty years have witnessed the most remarkable breakthroughs in our understanding of the molecular and cellular mechanisms that underpin circadian (approximately one day) time-keeping. Across model organisms in diverse taxa: cyanobacteria (Synechococcus), fungi (Neurospora), higher plants (Arabidopsis), insects (Drosophila) and mammals (mouse and humans), a common mechanistic motif of delayed negative feedback has emerged as the Deus ex machina for the cellular definition of ca. 24 h cycles. This review will consider, briefly, comparative circadian clock biology and will then focus on the mammalian circadian system, considering its molecular genetic basis, the properties of the suprachiasmatic nucleus (SCN) as the principal circadian clock in mammals and its role in synchronising a distributed peripheral circadian clock network. Finally, it will consider new directions in analysing the cell-autonomous and circuit-level SCN clockwork and will highlight the surprising discovery of a central role for SCN astrocytes as well as SCN neurons in controlling circadian behaviour. Full article
(This article belongs to the Special Issue Biological Clocks)
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26 pages, 2808 KiB  
Review
Selectable Markers and Reporter Genes for Engineering the Chloroplast of Chlamydomonas reinhardtii
by Lola Esland, Marco Larrea-Alvarez and Saul Purton
Biology 2018, 7(4), 46; https://doi.org/10.3390/biology7040046 - 10 Oct 2018
Cited by 42 | Viewed by 17509
Abstract
Chlamydomonas reinhardtii is a model alga of increasing interest as a cell factory for the production of valuable compounds, including therapeutic proteins and bioactive metabolites. Expression of foreign genes in the chloroplast is particularly advantageous as: (i) accumulation of product in this sub-cellular [...] Read more.
Chlamydomonas reinhardtii is a model alga of increasing interest as a cell factory for the production of valuable compounds, including therapeutic proteins and bioactive metabolites. Expression of foreign genes in the chloroplast is particularly advantageous as: (i) accumulation of product in this sub-cellular compartment minimises potential toxicity to the rest of the cell; (ii) genes can integrate at specific loci of the chloroplast genome (plastome) by homologous recombination; (iii) the high ploidy of the plastome and the high-level expression of chloroplast genes can be exploited to achieve levels of recombinant protein as high as 5% total cell protein; (iv) the lack of any gene silencing mechanisms in the chloroplast ensures stable expression of transgenes. However, the generation of C. reinhardtii chloroplast transformants requires efficient methods of selection, and ideally methods for subsequent marker removal. Additionally, the use of reporter genes is critical to achieving a comprehensive understanding of gene expression, thereby informing experimental design for recombinant applications. This review discusses currently available selection and reporter systems for chloroplast engineering in C. reinhardtii, as well as those used for chloroplast engineering in higher plants and other microalgae, and looks to the future in terms of possible new markers and reporters that will further advance the C. reinhardtii chloroplast as an expression platform. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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14 pages, 607 KiB  
Review
Applications of Microalgal Biotechnology for Disease Control in Aquaculture
by Patai Charoonnart, Saul Purton and Vanvimon Saksmerprome
Biology 2018, 7(2), 24; https://doi.org/10.3390/biology7020024 - 12 Apr 2018
Cited by 90 | Viewed by 15201
Abstract
Aquaculture industries, and in particular the farming of fish and crustaceans, are major contributors to the economy of many countries and an increasingly important component in global food supply. However, the severe impact of aquatic microbial diseases on production performance remains a challenge [...] Read more.
Aquaculture industries, and in particular the farming of fish and crustaceans, are major contributors to the economy of many countries and an increasingly important component in global food supply. However, the severe impact of aquatic microbial diseases on production performance remains a challenge to these industries. This article considers the potential applications of microalgal technology in the control of such diseases. At the simplest level, microalgae offer health-promoting benefits as a nutritional supplement in feed meal because of their digestibility and high content of proteins, lipids and essential nutrients. Furthermore, some microalgal species possess natural anti-microbial compounds or contain biomolecules that can serve as immunostimulants. In addition, emerging genetic engineering technologies in microalgae offer the possibility of producing ‘functional feed additives’ in which novel and specific bioactives, such as fish growth hormones, anti-bacterials, subunit vaccines, and virus-targeted interfering RNAs, are components of the algal supplement. The evaluation of such technologies for farm applications is an important step in the future development of sustainable aquaculture. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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15 pages, 2459 KiB  
Article
Age-Dependence and Aging-Dependence: Neuronal Loss and Lifespan in a C. elegans Model of Parkinson’s Disease
by Javier Apfeld and Walter Fontana
Biology 2018, 7(1), 1; https://doi.org/10.3390/biology7010001 - 23 Dec 2017
Cited by 11 | Viewed by 7319
Abstract
It is often assumed, but not established, that the major neurodegenerative diseases, such as Parkinson’s disease, are not just age-dependent (their incidence changes with time) but actually aging-dependent (their incidence is coupled to the process that determines lifespan). To determine a dependence on [...] Read more.
It is often assumed, but not established, that the major neurodegenerative diseases, such as Parkinson’s disease, are not just age-dependent (their incidence changes with time) but actually aging-dependent (their incidence is coupled to the process that determines lifespan). To determine a dependence on the aging process requires the joint probability distribution of disease onset and lifespan. For human Parkinson’s disease, such a joint distribution is not available, because the disease cuts lifespan short. To acquire a joint distribution, we resorted to an established C. elegans model of Parkinson’s disease in which the loss of dopaminergic neurons is not fatal. We find that lifespan is not correlated with the loss of individual neurons. Therefore, neuronal loss is age-dependent and aging-independent. We also find that a lifespan-extending intervention into insulin/IGF1 signaling accelerates the loss of specific dopaminergic neurons, while leaving death and neuronal loss times uncorrelated. This suggests that distinct and compartmentalized instances of the same genetically encoded insulin/IGF1 signaling machinery act independently to control neurodegeneration and lifespan in C. elegans. Although the human context might well be different, our study calls attention to the need to maintain a rigorous distinction between age-dependence and aging-dependence. Full article
(This article belongs to the Special Issue Systems Biology of Aging)
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32 pages, 4196 KiB  
Review
Anaphase A: Disassembling Microtubules Move Chromosomes toward Spindle Poles
by Charles L. Asbury
Biology 2017, 6(1), 15; https://doi.org/10.3390/biology6010015 - 17 Feb 2017
Cited by 51 | Viewed by 32542
Abstract
The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting [...] Read more.
The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting fibers, and anaphase B, separation of the two poles from one another via spindle elongation. I focus here on anaphase A chromosome-to-pole movement. The chapter begins by summarizing classical observations of chromosome movements, which support the current understanding of anaphase mechanisms. Live cell fluorescence microscopy studies showed that poleward chromosome movement is associated with disassembly of the kinetochore-attached microtubule fibers that link chromosomes to poles. Microtubule-marking techniques established that kinetochore-fiber disassembly often occurs through loss of tubulin subunits from the kinetochore-attached plus ends. In addition, kinetochore-fiber disassembly in many cells occurs partly through ‘flux’, where the microtubules flow continuously toward the poles and tubulin subunits are lost from minus ends. Molecular mechanistic models for how load-bearing attachments are maintained to disassembling microtubule ends, and how the forces are generated to drive these disassembly-coupled movements, are discussed. Full article
(This article belongs to the Special Issue Mechanisms of Mitotic Chromosome Segregation)
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